SAN FRANCISCO — Nearly 160,000 young Jews from North America have taken part in Taglit-Birthright Israel, a 10-day free Israel trip aimed at revving up their Jewish identities.

Of those no longer in college, only half have attended any Jewish event since their return.

That’s one of the findings of “Tourists, Travelers and Citizens,” a new report by the Cohen Center of Modern Jewish Studies at Brandeis University. The report is based on interviews and online surveys of 1,534 Birthright alumni in New York, Los Angeles, San Francisco and Toronto, the four largest Jewish communities in North America.

“It means we have a lot of work to do,” says Daniel Brenner, executive director of Birthright Israel NEXT, a national organization that tries to steer alumni toward greater Jewish involvement in their home communities.

The Birthright program was instituted in 2000 by mega-philanthropists concerned about what they perceived as the younger generation’s lack of Jewish involvement. Numerous formal and informal evaluations show participants’ connection to Israel and the Jewish community are enhanced by their trip, but that does not translate into ongoing Jewish involvement, according to the new report.

“Years after their trip, Taglit alumni continue to look more like ‘tourists’ than ‘citizens’ in the Jewish community world,” the report’s authors write. “Although they value their Jewish identities, most have only limited participation in Jewish communal life.”

The report shows that 44 percent of Birthright alumni who are no longer in college have not attended any Jewish program since their return from Israel. A further 39 percent have attended just one or two programs. Only 4 percent have taken part in more than four programs.

Toronto shows the greatest success at keeping this population somewhat engaged, with 63 percent of returnees participating in at least one Jewish event. Report co-author Fern Chertok attributes that to the close-knit nature of Toronto’s Jewish community, which keeps Birthright returnees apprised of a well-planned schedule of Jewish programs.

In New York, where 43 percent of returnees have not attended any Jewish program since their Israel trip, researchers found an array of Jewish offerings but little effort to communicate that information to Birthright alumni. Asked whether they had even heard of a dozen Jewish organizations offering programs for their age, the largest number — 67 percent — said they knew of the JCC Manhattan and the Y’s at 92nd Street and 14th Street, but just 20 percent had attended events there. Other Jewish programs showed even less participation and were lesser known.

Los Angeles showed the greatest number of completely disengaged alumni, with 53 percent saying they had attended no Jewish programs since Israel. San Francisco had higher numbers of alumni taking part in one to four activities — 43 percent and 10 percent, respectively — but just 1 percent who said they attended five or more.

Both California cities are hampered by a lack of good programs, say the report’s authors. Those that exist, particularly “Friday Night Live in L.A.” and the “Bay Area Tribe” and “Late Shabbat” in San Francisco, are high profile and do draw crowds.

The alumni surveyed in all four cities said they would like to be more involved than they were in Jewish life. Most preferred small gatherings to large, anonymous “meat market” Jewish events.

“They’re happy to eat free food and drink free beer at those big events, but they don’t feel it meets their needs to find Jewish community,” Chertok

reports.

Respondents also said they were interested in learning more about Judaism and Jewish culture and history, including Hebrew, but were wary of outreach groups with a perceived “religious” agenda. They also wanted a network of friends to share those experiences as a way of re-creating the camaraderie they felt on their Israel trips.

“Birthright shows people that being part of a group, a Jewish group, is a meaningful experience,” report co-author Leonard Saxe says. “They come back hungry for that, and most communities don’t provide them with a set of those experiences.”